Method for controlling washing machine

ABSTRACT

A method for controlling a washing machine is disclosed. The method includes determining whether a discharging condition is satisfied, and if the discharging condition is satisfied, discharging water in a steam generator out of the steam generator. Accordingly, deposit of foreign substances in the steam generator can be effectively prevented. Further, since the deposit of the foreign substances in the steam generator is automatically prevented, the convenience in usage of the washing machine is increased.

This application claims the benefit of Korean Patent Application No. 10-2006-0002009, filed on Jan. 6, 2006, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine, and more particularly to a method for controlling a washing machine which can remove foreign substances that may be deposited in a steam generator of a washing machine.

2. Discussion of the Related Art

Generally, a washing machine is classified into a pulsator type washing machine which washes laundry by water current generated by rotating a pulsator, and a drum type washing machine which washes laundry by drop and frictional force of washing water and laundry generated by rotating a horizontally mounted drum.

Recently, a drum type washing machine which washes laundry by using steam has been proposed. If using steam for washing laundry, water and electricity can be saved, and washing performance can be improved. Also, creases and odor can be removed.

A conventional drum type washing machine using steam will now be described with reference to FIG. 1.

The conventional drum type washing machine includes a cabinet 10 which forms an external appearance, a cylindrical tub 20 which is horizontally mounted in the cabinet 10 and contains washing water, a drum 30 which is rotatably mounted in the tub 20, and a driving motor (not shown) which drives the drum 30. The cabinet 10 is provided with an opening 13 at a front panel, which is communicated with the inside of the drum 30 for throwing laundry into the drum 30 and taking laundry out of the drum 30, and a door 11 for opening and closing the opening 13. The drum type washing machine further includes a water-supply valve 15 which is connected to an external water pipe (not shown) to supply washing water into the tub 20. A hot-water pipe 25 a and a cold-water pipe 26 extend from the water-supply valve 15 to a detergent box 27.

The drum type washing machine further includes a steam generator 50 for supplying steam into the drum 30. A water-supply hose 25 and a steam-supply pipe 53 for guiding the generated steam into the drum 30 are connected to the steam generator 50. The water-supply hose 25 is typically connected to a hot-water side of the water-supply valve 15. The steam-supply pipe 53 has a nozzle-shaped front end so as to effectively inject steam into the drum 30, which is exposedly mounted to the inside of the drum 30.

Referring to FIGS. 2 and 3, a structure of the steam generator 50 will now be described in detail.

The steam generator 50 includes a housing 80 which has a lower housing 81 which forms an outer appearance and provides a space for storing water and an upper housing 82 which is coupled to an upper portion of the lower housing 81, and a heater 55 which heats the water stored in the housing 80.

The upper housing 82 is formed with a water-supply port 52 a to which the water-supply hose 25 is connected to guide the water into the housing 80, and a discharge port 52 b to which the steam-supply pipe 53 is connected to supply the generated steam into the drum 20.

The heater 55 is mounted to a lower portion in the lower housing 81 so as to be immersed in the water flowing into the housing 80 of the steam generator 50. In order to operate the heater 55 while the heater 55 is immersed in the water, a water level sensor 60 is mounted to the upper housing 82 of the steam generator 50. The water level sensor 60 measures the water level in the housing 80, so that the water level in the housing 80 can be always kept to an adequate level. In other words, when the water level in the housing 80 of the steam generator 50 is less than a preset reference level, the water-supply valve 15 is opened to supplement water. When the water level in the housing 80 is the reference level or more, the water-supply valve 15 is closed to stop the water supply, and the heater 55 is operated to generate steam.

Also, a temperature sensor 57 is mounted to the upper housing 82 of the steam generator 50 to measure temperature of the water heated by the heater 55 and the steam. When the temperature measured by the temperature sensor 57 is a preset reference value or more, the power applied to the heater 55 is interrupted to prevent overheating of the heater 55.

Describing the water level sensor 60 in detail, the water level sensor 60 includes a receptacle housing 61 which forms an outer appearance and is configured to be fixed to the upper housing 82 of the steam generator 50, and electrode parts 62, 63 and 64 which are mounted downward at the receptacle housing 61 and sense the water level in the housing 80 of the steam generator 50.

The electrode parts 62, 63 and 64 extend downward from the receptacle housing 61 to respectively adequate heights from a bottom of the lower housing 81.

However, the above-described washing machine, especially the steam generator has a problem that foreign substances are deposited in the steam generator.

Especially, when the steam generator is used for a long time, the foreign substances are severely deposited in the steam generator. Typically, the foreign substances are mainly contained in the water supplied into the steam generator, if the water is not pure, the foreign substances are more severely deposited in the steam generator. If the foreign substances are deposited in the steam generator, performance deterioration of the steam generator like malfunction of the water level sensor is generated, and durability of the steam generator is decreased.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method for controlling a washing machine that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method for controlling a washing machine which can effectively prevent foreign substances from being deposited in a steam generator.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve the object and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method for controlling a washing machine comprises: a) determining whether a discharging condition is satisfied; and b) if the discharging condition is satisfied, discharging water in a steam generator out of the steam generator.

The discharging condition may include a command inputted by a user to perform the discharging step b).

Preferably, the discharging condition includes a command inputted by a user to drive the washing machine. More preferably, the command inputted by the user to drive the washing machine is selection of a steam course. Preferably, the determining step a) includes: additionally determining whether additional discharging conditions are satisfied. Preferably, the additional discharging conditions are determined based on a preset heating temperature and a detected water temperature in a tub according to the selected steam course. Preferably, the water temperature in the tub is detected right after completion of water supply.

Preferably, the additionally determining step is performed based on a difference between the heating temperature and the water temperature in the tub, and a rising temperature in the tub while discharging the water out of the steam generator at one cycle. Preferably, the discharging step b) includes: discharging the water out of the steam generator once.

In another aspect of the present invention, during operation of the steam course, a door is controlled to be locked for a predetermined time, and the door is unlocked after elapse of the predetermined time.

In yet another aspect of the present invention, the discharging step b) includes: discharging the water out of the steam generator through a drain port.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a perspective view illustrating a structure of a conventional drum type washing machine;

FIG. 2 is a perspective view illustrating a steam generator of a conventional drum type washing machine;

FIG. 3 is a partial cut-away perspective view of a steam generator depicted in FIG. 2;

FIG. 4 is a flow chart of a method for controlling a washing machine in accordance with the present invention; and

FIG. 5 is a flow chart of one particular embodiment of a method for controlling a washing machine depicted in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention associated with a method for controlling a washing machine, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Since a washing machine and a steam generator themselves are substantially the same as the aforesaid conventional washing machine and steam generator, detailed description thereof will be omitted.

Referring to FIG. 4, a method for controlling a washing machine (especially, a drum type washing machine) according to the present invention will now be described.

Generally, a washing process of a washing machine includes a washing operation, a rinsing operation and a dehydrating operation. The washing operation and the rinsing operation typically include a water-supply operation. And, a laundry soaking operation may be performed before the washing operation. When steam is used in the washing machine, steam is injected into a drum during the washing operation and/or the rinsing operation. In order to inject the steam, the steam generator is operated. There are various steam injection methods, however, the description thereof will be omitted.

The washing machine is operated by a manual driving method for individually performing the washing operation, the rinsing operation and the dehydrating operation, and an automatic driving method for automatically performing all of the above operations of the washing process. In the case of the automatic driving, according to the kind of laundry and the extent of contamination, driving conditions at the respective operations (e.g., a water level, the number of rinse operations and the like) are predetermined.

While the washing machine is operated, foreign substances, especially lime, may be deposited in the steam generator. Accordingly, it is needed to remove the foreign substances from the steam generator. To this end, the steam generator can be configured such that a drain part is mounted to a lower portion of the steam generator, so as to discharge the foreign substances through the drain part with regular periods. However, in this removal structure, it is very inconvenient for a user or a repairman to directly open the drain part to discharge the foreign substances. To obviate this problem, the present invention provides a method for controlling a washing machine which can simply and conveniently discharge the foreign substances.

The present invention is configured such that when prescribed conditions are satisfied, the water stored in the steam generator is automatically discharged out of the steam generator. At this time, because the foreign substances are discharged together with the water, the deposit of the foreign substances in the steam generator can be effectively prevented.

Hereinafter, a principle of discharging the water from the steam generator to the drum will be described.

As shown in FIGS. 1 and 2, the steam generator 50 is formed with the water-supply port 52 a for guiding the water into the steam generator 50, and the discharge port 52 b for discharging the steam into the drum 30. One end of the steam-supply pipe 53 is connected to the discharge port 52 b, and the other end is connected to the drum 30. Commonly, when the water level in the steam generator 50 rises to the reference level or more and the water level sensor 60 outputs a high water-level sensing signal, the water supply into the steam generator 50 is stopped. If the water is continuously supplied into the steam generator 50 even when the water level in the steam generator 50 rises to the high water level, the supplied water is discharged to the drum 30 through the discharge port 52 b and the steam-supply pipe 53. Because the discharge port 52 b is disposed above the high water level, it can be considered that the water in the steam generator 50 overflows through the discharge port 52 b.

As described above, the method for controlling the washing machine according to the present invention includes: determining whether the prescribed conditions for discharging the water out of the steam generator (hereinafter, which will be called “discharging conditions”) are satisfied at step S1; and if it is determined that the discharging conditions are satisfied, discharging the water out of the steam generator at step S3.

The discharging conditions can be determined by various methods, however, it is preferable to be determined in consideration of user's convenience. For example, by providing an additional discharge button at a manipulation panel of the washing machine, a user can push the discharge button so that the discharging operation is performed.

On the other hand, it can be more preferable that the discharging operation is performed while the user is not conscious. In other words, during an operation of a washing process such as a washing operation and/or a rinsing operation, the discharging operation can be automatically performed for a predetermined time. At this time, while the water is discharged out of the steam generator, the heater in the steam generator may be controlled to be operated or not to be operated. In this case, the discharging condition becomes a user's command to start an operation such as the washing operation or the rinsing operation. User can command to start the operation by selecting a washing process and pressing a start button for initiating the washing process. Alternatively, User can also command to start the operation by selecting the operation only and pressing a start button for initiating the operation only.

Meanwhile, during the manual driving or the automatic driving of the washing machine, the user can select a so-called “steam course” for washing laundry by using steam. It is preferable to perform the operation of discharging the water out of the steam generator only when the steam course is selected. This is because the water is not necessarily discharged out of the steam generator at every operation of the washing machine. Also, because the heater is operated to heat the water when the steam course is selected, to discharge the water out of the steam generator is needed.

The washing process when selecting the steam course will now be described in detail.

When the steam course is selected, a temperature of the water in the tub is preset to a predetermined value T1 (hereinafter, which will be called a “heating temperature”), and the washing machine is controlled so that the temperature of the water in the tub becomes the heating temperature T1. A temperature of the water supplied into the tub is also preset to a predetermined value (hereinafter, which will be called a “water supply temperature”), and the water supply temperature is adjusted by adequately mixing the cold water and the hot water. For instance, in the case of the washing machine which is on the market in North America, when the material of laundry is cotton and the extent of contamination is normal, the heating temperature is set to 56° C., and the water supply temperature is set to a range of 45° C. to 50° C.

In the discharging step S3, the water is discharged out of the steam generator for a predetermined time (hereinafter, which will be called a “cycle”), and a temperature rising value T3 in the tub (hereinafter, which will be called a “rising temperature in the cycle”) by the water discharged during the cycle can be derived. For example, the degree of temperature rise of the water in the tub while the water is discharged during one cycle can be derived from experiments for each product, each load, and each voltage. In conclusion, as the additional discharging conditions when selecting the steam course, the preset heating temperature T1, the water supply temperature T2 and the rising temperature in the cycle T3 according to the selected steam course can be used.

Referring to FIG. 5, a particular embodiment of the method for controlling the washing machine will now be described.

It is determined whether the steam course is selected at step S11. If it is determined that the steam course is selected, the preset heating temperature T1 according to the selected steam course is determined as step S13. Then, the water temperature T2 in the tub is detected at step S15. At this time, it is preferable to detect the water temperature T2 in the tub right after the completion of the water supply. However, when the water-supply time exceeds a predetermined time by a certain reason, e.g., a large amount of laundry, it is preferable to detect the water temperature T2 in the tub after the predetermined time elapses from the water-supply starting time.

Afterwards, by using a ratio of a difference T between the preset heating temperature T1 and the detected water temperature T2 in the tub (i.e., T=T1−T2) to the rising temperature in the cycle T3, the number of cycles of discharging the water out of the steam generator are calculated at step S17. If it is determined that the number of cycles are larger than 1 at step 19, the discharging operation is performed at step S21. At this time, it is preferable to perform the discharging operation once.

As described above, if performing the discharging operation when the steam course is selected, since the water heated in the steam generator is supplied into the drum, the time and energy required for the water temperature in the drum to reach the heating temperature can be saved.

In the above description, it has been explained that the water in the steam generator is discharged into the drum, however, the present invention is not restricted thereto. For example, a drain part having a valve may be mounted to the steam generator, and the water can be discharged out of the steam generator through the drain part by controlling the valve.

For the user's safety, during the operation of the steam course, the door is controlled to be locked for a predetermined time so that the user cannot open the door, and the door is unlocked after the elapse of the predetermined time.

In addition, the steam generator according to the present invention can also be applied to a dryer using steam. In this case, the water in the steam generator is discharged outside through a drain part.

As apparent from the above description, according to the method for controlling the washing machine in accordance with the present invention, if the prescribed conditions are satisfied, the water in the steam generator is discharged out of the steam generator, and simultaneously the foreign substances are discharged together with the water. Accordingly, the deposit of the foreign substances in the steam generator can be effectively prevented. Further, since the deposit of the foreign substances in the steam generator is automatically prevented, the convenience in usage of the washing machine is increased.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A method for controlling a washing machine, comprising: a) determining whether a discharging condition is satisfied; and b) if the discharging condition is satisfied, discharging water in a steam generator out of the steam generator.
 2. The method according to claim 1, wherein the discharging step b) includes: supplying the water so that the water in the steam generator overflows and is discharged through a steam discharge port.
 3. The method according to claim 1, wherein the discharging condition includes a command inputted by a user to perform the discharging step b).
 4. The method according to claim 1, wherein the discharging condition includes a command inputted by a user to drive the washing machine.
 5. The method according to claim 4, wherein the command inputted by the user to drive the washing machine includes selection of a steam course.
 6. The method according to claim 5, wherein the determining step a) includes: additionally determining whether additional discharging conditions are satisfied.
 7. The method according to claim 6, wherein the additional discharging conditions are determined based on a preset heating temperature and a detected water temperature in a tub according to the selected steam course.
 8. The method according to claim 7, wherein the water temperature in the tub is detected right after completion of water supply.
 9. The method according to claim 7, wherein the additionally determining step is performed based on a difference between the heating temperature and the water temperature in the tub, and a rising temperature in the tub while discharging the water out of the steam generator at one cycle.
 10. The method according to claim 9, wherein the discharging step b) includes: discharging the water out of the steam generator once.
 11. The method according to claim 5, wherein during operation of the steam course, a door is controlled to be locked for a predetermined time, and the door is unlocked after elapse of the predetermined time.
 12. The method according to claim 1, wherein the discharging step b) includes: discharging the water out of the steam generator through a drain port. 